#include<string>
#include<iostream>
using namespace std;
int main()
{
    string s1("abc");
    string s2("1234");
    s1+=s2+"xyz";
    cout<<"s1:"<<s1<<endl;
    bool tag=s1>s2?true:false;
    cout<<"tag:"<<tag<<endl;
    int pos=2;
    s1.insert(pos,s2);
    string s3=s1.substr(pos,6);
};